.header{
    height:3rem;
    background-color: #d5d5d5;
    display: flex;
    align-items: center;
    justify-content: space-around;
}
.hrdescr{
    height:1px;
    border:none;
    border-top:1px solid #d9d9d9;
    width: 87vw;
    margin-left: 2rem;
}
/*.header > a:first-of-type{
    margin-left: -2rem;
}*/
.chapter-list{
    display: flex;
    flex-flow: column nowrap;
    text-align: center;
}
.chapter-list > a{
    margin-top: 1.3rem;
}
.chapter-desc{
    height:3rem;
    background-color: white;
    margin-top: 0.2rem;
    display: flex;
    justify-content: space-around;
    align-items: center;
    font-size: 1rem;
    font-weight:bold;
}
.chapter-desc > a > img{
    width: 1.5rem;
    height: 1.5rem;
}
.chapter-list{
    margin-top: 0.2rem;
    background-color: white;
}